The present invention relates to a multi-inlet vacuum pump.
Multi-inlet vacuum pumps comprise, within a common housing, a plurality of pump devices provided e.g. as turbomolecular pumps, optionally in connection with a Holweck stage. Usually, the individual pump devices are carried by a common rotor shaft and are driven by a single electric motor. The pump housing comprises a main inlet through which a first fluid stream is sucked in by operation of the first pump device. Then, after passing through the first pump device, the first fluid stream will be conveyed in the direction of an outlet by the second pump device and, optionally, by further pump devices. Between the first and second pump devices, an intermediate inlet is provided for suctional intake of a second fluid stream by operation of the second pump device. The second pump device will thus convey the first and second fluid streams in the direction of the outlet. Optionally, a second intermediate inlet can be provided between the second pump device and a third pump device. By operation of the third pump device, also a corresponding third fluid stream is conveyed in the direction of the outlet, wherein all of said three fluid streams will be conveyed by the third pump device.
It is an object of the invention to provide a multi-inlet vacuum pump having a high suction capacity in said intermediate inlet.